Power efficient resource allocation in uplink SC-FDMA systems

In this paper, we study sum-power minimization problem in SC-FDMA which is adopted as the multiple access scheme for uplink in the 3GPP-LTE standard. Unlike OFDMA, in addition to the restriction of allocating a sub-channel to one user at most, the multiple sub-channels allocated to a user in SC-FDMA should be consecutive as well. This renders the resource allocation problem prohibitively difficult and the standard optimization tools (e.g., Lagrange dual approach widely used for OFDMA, etc.) can not help towards its optimal solution. We propose a novel polynomial-complexity optimization framework that is inspired from the recently developed canonical duality theory. We first formulate the resource allocation problem as a binary-integer programming (BIP) problem and then transform the BIP problem into a continuous space canonical dual problem which is a concave maximization problem under certain conditions. Based on the solution of the canonical dual problem, we derive a joint power and sub-channels allocation algorithm that has polynomial complexity. We provide conditions under which the proposed algorithm is optimal. The proposed framework is illustrated through simulations where the results show that the proposed algorithm improves the system performance significantly.